The USB camera module is the “digital pupil” of a spectral scanner. While ultraviolet, visible, and near-infrared light sources illuminate a document in rapid succession, the module must capture each high-dynamic, wide-band image within milliseconds and stream the lossless frames over USB 3.0 to the host. AI algorithms then perform pixel-level comparisons of micro-text, holographic threads, and IR watermarks—any 1 µm ink absence or spectral deviation is immediately flagged. In short, imaging resolution, quantum efficiency, and synchronization accuracy determine whether the final forensic report can stand as legal evidence.
Selection can be distilled into four keywords: light, sensor, cable, sync. The sensor must retain high sensitivity from 254–1100 nm and incorporate UV-IR correction; global shutter and ≥12-bit ADC ensure that bright fluorescence and dark recesses coexist in one frame; an FPC ribbon offers both flexibility and shielding, bending through tight optical paths while rejecting EMI; external trigger and on-board frame buffering lock timing to filter wheels or pulsed light sources within microseconds. Only when all four criteria are met can the scanner deliver a truly trustworthy digital evidential chain.
